package redisactivity

import (
	"context"
	"encoding/hex"

	"proxy-pool/internal/domain/activitypool"
	healthDomain "proxy-pool/internal/domain/health"
)

var _ activitypool.HealthStore = (*Adapter)(nil)
var _ activitypool.GlobalHealthStore = (*Adapter)(nil)

func (a *Adapter) ApplyHealth(ctx context.Context, update activitypool.HealthUpdate) (activitypool.Entry, error) {
	if ctx == nil {
		return activitypool.Entry{}, activitypool.ErrInvalidHealthUpdate
	}
	if err := ctx.Err(); err != nil {
		return activitypool.Entry{}, err
	}
	if a == nil || update.ProxyID == "" || update.CheckedAt.IsZero() || update.Latency < 0 ||
		!validProxyState(string(update.NextState)) {
		return activitypool.Entry{}, activitypool.ErrInvalidHealthUpdate
	}
	operationID, err := newOperationID()
	if err != nil {
		return activitypool.Entry{}, err
	}
	result, err := runScript(ctx, a.client, healthScript, []string{
		a.keys.records, a.keys.unique, a.keys.idkeys, a.keys.expiry, a.keys.available,
		a.keys.inventory, a.keys.stateInventory, a.keys.owners, a.keys.ownerExpiry,
		a.keys.operation(operationID),
	}, update.CheckedAt.UnixMilli(), string(update.NextState), int64(update.Latency),
		a.options.CleanupLimit, operationTTLMillis(a.options.OperationTTL), update.ProxyID)
	if err != nil {
		return activitypool.Entry{}, err
	}
	var reply healthScriptReply
	if err := decodeScriptResult(result, &reply); err != nil {
		return activitypool.Entry{}, err
	}
	switch reply.Status {
	case scriptNotFound:
		return activitypool.Entry{}, activitypool.ErrActivityNotFound
	case scriptStale:
		return activitypool.Entry{}, activitypool.ErrStaleHealthUpdate
	case scriptInvalid:
		return activitypool.Entry{}, activitypool.ErrInvalidHealthUpdate
	case scriptOK:
		if reply.Record == "" {
			return activitypool.Entry{}, invalidScriptReply("health reply omitted record")
		}
		record, err := decodeProxyRecord(reply.Record)
		if err != nil {
			return activitypool.Entry{}, invalidScriptReply("health reply contained an invalid record")
		}
		return proxyRecordEntry(record), nil
	default:
		return activitypool.Entry{}, invalidScriptReply("unexpected health status")
	}
}

// ApplyGlobalObservation reduces one BASIC or EGRESS observation inside the
// same Redis Lua transaction that updates state indexes and inventory.
func (a *Adapter) ApplyGlobalObservation(
	ctx context.Context,
	command activitypool.GlobalHealthCommand,
) (activitypool.Entry, error) {
	if ctx == nil {
		return activitypool.Entry{}, activitypool.ErrInvalidHealthUpdate
	}
	if err := ctx.Err(); err != nil {
		return activitypool.Entry{}, err
	}
	normalized, err := healthDomain.NormalizeObservation(command.Observation)
	if err != nil {
		return activitypool.Entry{}, err
	}
	if a == nil || normalized.Level == healthDomain.LevelTarget || command.MaxConsecutiveFailures <= 0 {
		return activitypool.Entry{}, activitypool.ErrInvalidHealthUpdate
	}
	digest, err := healthDomain.ObservationDigest(normalized)
	if err != nil {
		return activitypool.Entry{}, err
	}
	operationID, err := newOperationID()
	if err != nil {
		return activitypool.Entry{}, err
	}
	success := "0"
	if normalized.Success {
		success = "1"
	}
	result, err := runScript(ctx, a.client, healthScript, []string{
		a.keys.records, a.keys.unique, a.keys.idkeys, a.keys.expiry, a.keys.available,
		a.keys.inventory, a.keys.stateInventory, a.keys.owners, a.keys.ownerExpiry,
		a.keys.operation(operationID),
	}, normalized.ObservedAt.UnixMilli(), "", int64(normalized.Latency),
		a.options.CleanupLimit, operationTTLMillis(a.options.OperationTTL), normalized.ProxyID,
		"global", success, command.MaxConsecutiveFailures, normalized.TaskID, hex.EncodeToString(digest[:]))
	if err != nil {
		return activitypool.Entry{}, err
	}
	var reply healthScriptReply
	if err := decodeScriptResult(result, &reply); err != nil {
		return activitypool.Entry{}, err
	}
	switch reply.Status {
	case scriptNotFound:
		return activitypool.Entry{}, activitypool.ErrActivityNotFound
	case scriptStale:
		return activitypool.Entry{}, healthDomain.ErrStaleObservation
	case scriptConflict:
		return activitypool.Entry{}, healthDomain.ErrConflictingObservation
	case scriptInvalid:
		return activitypool.Entry{}, activitypool.ErrInvalidHealthUpdate
	case scriptOK:
		if reply.Record == "" {
			return activitypool.Entry{}, invalidScriptReply("global health reply omitted record")
		}
		record, err := decodeProxyRecord(reply.Record)
		if err != nil {
			return activitypool.Entry{}, invalidScriptReply("global health reply contained an invalid record")
		}
		return proxyRecordEntry(record), nil
	default:
		return activitypool.Entry{}, invalidScriptReply("unexpected global health status")
	}
}